HOUSTON — Terra Black, 11, awoke on her first day of sixth grade on a cot in the middle of a sprawling convention hall in downtown Houston, the place she has called home since escaping neck-deep floodwater that threatened her family’s apartment. Here, in bathrooms she shares with about 1,400 other evacuees, she got ready for school, styling her hair and slipping on a pink T-shirt her mother had snatched from a donation pile.

“I’m a little nervous,” Terra said later, grinning widely as she munched on a breakfast sandwich at a nearby Walmart. “It’s a new year, a new learning experience.”

Tens of thousands of schoolchildren returned to school Monday, two weeks after Hurricane Harvey battered the city, flooding homes, sweeping away uniforms and school supplies, and shuttering one of the nation’s largest school districts.

For a city in recovery — and especially for displaced children such as Terra — the reopening of 268 of the district’s 280 schools represents a critical step toward normalcy in a city where thousands of homes remain uninhabitable and where signs of the storm still abound.

Terri Black shops for school supplies at a Walmart with her daughters Terra Black, 11, and Edahlia Payne, 4. (Tamir Kalifa for The Washington Post)

Public officials heralded the reopening of the schools as one of the surest signs the region was bouncing back.

“We have let the nation and the world know that the city is back in business, and one way of demonstrating that is for the schools to be open, for the kids to be learning, for the bands to be playing, for our athletes to be performing,” Houston Mayor Sylvester Turner said at a news conference in the school library at Bruce Elementary. “Nothing better than Texas football.”

But while educators celebrated the return of students, they braced for the myriad challenges students face in the storm’s aftermath: missing school days, lost school supplies and uniforms, psychological trauma and transience. There were teachers, too, who lost everything, and about 270 were unable to return to work Monday.

There was also the financial toll: Superintendent Richard A. Carranza estimates the storm will cost the district roughly $700 million, a third of the annual budget.

Carranza said the district was attempting to meet the needs created by the storm. The district is providing breakfast, lunch and dinner to all schoolchildren this year, regardless of their families’ incomes. It also relaxed requirements so families who were forced to move and could not find lost birth certificates and other records would be able to move to new schools.

As the sun rose Monday, Ruth Rojas walked her two children, 9-year-old Adrian and 11-year-old Joseline, out of the convention center, where they have lived since the Coast Guard rescued them from their home north of Houston.

School buses are parked outside of the George R. Brown Convention Center, which became a shelter in Harvey’s wake. (Tamir Kalifa for The Washington Post)

The siblings had attended school in a suburban district, but Rojas was unsure when — or if — they would be able to return home. So with the help of school staff stationed inside the sprawling shelter, she registered them at two local schools: Red Elementary and Meyerland Middle. She was relieved she did not have to have her children’s paperwork, which is locked in a car flooded during the hurricane.

A yellow school bus fetched the childrenfrom the convention ­center.

“I want them to keep up with everything. I didn’t want them to get behind,” said Rojas, who added that her daughter was in the gifted program. “It was important for me and for them.”

Parents said they hoped the return to school would be therapeutic for their children, whose lives and routines have been upended by the storm. Stephanie Melton-Curtis escaped the storm with her family by walking about two miles through chest-deep water, with her husband, Travis Curtis, carrying their 3-year-old daughter, Talayah, on his shoulders. Later, Talayah came home and asked why her bed and toys were in a pile on the curb.

Melton-Curtis worries the experience scarred Talayah and welcomed the chance for her to start prekindergarten.

“I think it will take her mind off of it,” Melton-Curtis said. “She won’t have to worry.”

Many schoolchildren like Terra and Talayah could recount similar stories of narrowly surviving the flood, which killed at least 22 people, including a family whose van was inundated by floodwater.

Carranza said the district was preparing teachers for the possibility that many children may arrive with psychological damage from the storm and its aftermath. The district planned to train all teachers in “trauma-informed pedagogy” and to dispatch crisis counselors to schools.

“This is going to be a year of incredible academic growth, but it’s also going to be a year of recovery,” Carranza said.

School was also a welcome respite from boredom for many children stuck at the convention center. Save the Children had set up a Kids Zone with arts and crafts and other activities, but there were otherwise few diversions.

At Gregory-Lincoln Education Center in Houston, Terra sat among her classmates in her English, language arts and reading class, working intently on a work sheet titled “All About Me,” asking for her favorite color and game and about her family.

Teacher Kathryn Green oriented students to the classroom, pointing out the motivational posters and an Oscar Wilde quote painted in loopy cursive on the wall: “It is what you read when you don’t have to that determines what you will be when you can’t help it.”

As she gestured around the room, Green urged the students to treat the space as if it were their own.

“This is your classroom. This is your homeroom. This is your home,” Green said insistently. “You guys are going to learn we’re a family.”